Planning for the weather is a good way to make your trip to Coonoor relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and March with an average temp of 71°F, while the coldest months are January and February with an average of 66°F. The rainiest months in Coonoor are October, July, August, and May, with each month seeing an average of 10 inches of rainfall.